RoofRainYield

Liberty, MO rainwater: 32,666 gallons off a roof

Liberty, MO: gallons off the roof each year

32,666gallons a year

That is a 1,500 sq ft asphalt roof under Liberty, MO's normal 41.1 inches of rain, about 795 gallons for every inch that falls.

In Liberty, MO a single barrel does most of the work. Storms come often enough that a small tank refills before it runs dry, and a bigger one would mostly sit full.

Rainfall: NOAA 1991-2020 climate normals, the Pleasant Valley 0.8 Nw station (3.9 mi away). Liberty, MO ranks 72nd wettest of the 80 cities covered in Missouri.

Month by month in Liberty

MonthRain (in)Off the roof (gal)Garden shortfall (gal)
Jan1.261,001
Feb1.551,232
Mar2.501,987
Apr4.193,33020
May5.634,475
Jun5.254,173
Jul4.813,823
Aug4.623,672
Sep4.143,29026
Oct3.352,663125
Nov2.141,701
Dec1.661,319

May is the wettest month (5.63 in, 4,475 gal off the roof); Jan the driest (1.26 in). Garden shortfall is what a 200 sq ft vegetable bed needs beyond the rain that lands on it, April to October.

What size rain barrel for Liberty

Best fit: one 55-gallon barrel, which delivers about 137 gallons to the garden in a normal year (80.2% of its need).

Before you buy, a 55-gallon barrel with a downspout diverter is the whole job. Check that the overflow points away from your foundation, because most of Liberty's roof water will pass straight through it.

TankWater used (gal/yr)Spills over (gal/yr)
55 gal13731,584
110 gal13731,584
165 gal13731,584
275 gal13731,584
550 gal13731,584
1,000 gal13731,584
1,500 gal13731,584
2,500 gal13731,584
5,000 gal13731,584

Simulated storm by storm through a normal year using the station's count of days with 0.1 in or more of rain each month.

Is rainwater collection legal in Missouri?

No rainwater harvesting regulations

From the 2015 (Pacific Northwest National Laboratory report 24347); not yet re-checked against current law, so check with your state water agency before building anything large. Source